EGR Backpressure Transducer: Testing and Inspection

Fig. 37 Testing Vacuum Modulator:

Fig. 38 Testing Vacuum Modulator:

1. Disconnect vacuum hoses from EGR vacuum modulator.
2. Place finger over the two end ports (P and R). Fig. 37
3. Blow air into the single port (Q).
4. Ensure air passes through the air filter side freely.
5. Start the engine and maintain engine speed at 3000 RPM.
6. Repeat test and ensure there is a strong resistance to air flow. Fig. 38
7. If a problem is found, replace the vacuum modulator.
8. Reconnect the vacuum hoses to their proper locations.